This invention relates to a firearm equipped with a safety device. More particularly, this invention relates to a firearm which has been modified to accept blank cartridges while rejecting live ammunition.
Safety in the storage and use of firearms has become an important issue. A particular safety issue is the prevention of inadvertent discharge of a weapon thought to be unloaded, or loaded with live ammunition when the weapon was thought to be loaded with a blank.
One approach to the safety issue is to provide a lock for the firearm which completely disables the weapon until the lock is removed. For example, Lavergne U.S. Pat. No. 4,654,992 describes a locking device for a firearm which fits into the receiver portion of the firearm through the magazine opening. When a barrel locking cylinder is turned via a key, an arm on the locking device is moved through the ejection port to completely block any loading of a cartridge into the firearm until the lock is removed.
The firearm may also be provided with means that block, or partially block loading of one type of standard cartridge while permitting another standard cartridge to be loaded. Typifying this approach is Jennie et al U.S. Pat. No. 3,990,169, which discloses a shotgun with interchangeable barrels chambered for different length shotgun shells. A lug is provided which extends from the end of the gun barrel chambered for shorter length shells into the receiver section of the gun over the magazine. This lug interferes with the automatic feeding of a longer shell from the magazine into the receiver section of the gun.
Another approach is to alter the firearm so that only a special cartridge may be used. For example, Cole U.S. Pat. No. 683,384 describes an elliptical projectile and a cartridge for same which cooperates with guides in the gun breech to provide proper seating for the cartridge and bullet.
Kerr U.S. Pat. No. 3,237,335 discloses a special firearm and a safety cartridge for use with the special firearm. A series of lugs circumferentially spaced around and protruding inwardly from the wall of the firing chamber of the firearm are received in corresponding slots in the rim of the safety cartridge. When the safety cartridge is inserted into the chamber, the cartridge is rotated until the lugs in the chamber and the slots in the cartridge rim are in registry. In another embodiment, a lug is provided on the rear wall of the firing chamber which matches with a groove formed across the rear end wall of the cartridge casing.
Francois U.S. Pat. No. 3,686,999 describes a firearm comprising a long tube in which are stored a number of missiles. Arranged along one side of the tube are a series of firing devices respectively for each missile. A locking pin in each firing device passes through an opening in the tube and fits into a recess in the respective missile. When the first firing device is activated, its detonator causes the locking pin in the first missile to retract from the recess.
While such safety devices are useful for the purposes intended, it would be desirable to provide a simple modification to a standard firearm, used for training and familiarization with the weapon, whereby only blanks could be fired with the modified firearm and live ammunition could not be fired. In this manner, personnel using the weapon for training purposes could become thoroughly familiar with the weapon, including even simulated firing of the weapon using blanks, without incurring any substantial risk of injury due to inadvertent loading of a live round into the firearm.